staging: lustre: remove ll_crypto_alloc_blkcipher

Turns out that the ll_crypto_alloc_blkcipher() wrapper didn't even do
anything, and is probably wrong, so it's not needed, just call the
crypto core directly.

Cc: Peng Tao <tao.peng@emc.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>